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Super Freak
If it were mine, I’d try to surgically apply some some rubber cement or epoxy with a pin. Just a tiny amount to close up the cut, and wipe away any excess.
If he heats the cut up first then put the cement in the cut and holds it together it might close up and stay closed. You think superglue would work better? it dries really fast. He could put a little on an exacto knife and get it into the cut.